There is a CSS (Content Scrambling System) as an encryption method adopted in a read-only type DVD. Moreover, there is a CPRM (Content Protection for Recordable Media) as an encryption method adopted in a recordable type DVD.
In the encryption method about DVD, there is such a history that the CSS was firstly spread and then the CPRM was spread. Because of such a history or the like, some old type players cannot reproduce the data that is encrypted by the CPRM.
Hereinafter, the player that cannot reproduce the data encrypted by the CPRM is referred to as a “first-generation” player, and the player that can reproduce the data encrypted by the CPRM is referred to as a “second-generation” player.
Incidentally, most DVD players, specially the second-generation DVD players, have not only a reproduction function of reproducing the data recorded on the DVD but also a recording function of recording the data onto the DVD. The product name is also not a “DVD player” but a “DVD recorder”. Here, however, for convenience of explanation, not only the apparatus having only the reproduction function but also the apparatus having both the reproduction function and the recording function are also referred to as the “player”.
By the way, in case of a read-only disc on which the data encrypted by the CSS is recorded, both the first-generation player and the second-generation player can perform the reproduction.
However, in case of a recordable type disc on which the data encrypted by the CSS is recorded, the first-generation player can perform the reproduction, but the second-generation player cannot perform the reproduction.
That is, the encryption method adopted in the recordable type disc is not the CSS but the CPRM. Therefore, the second-generation player recognizes the recordable type disc on which the data encrypted by the CSS is recorded, as an abnormal disc. Then, the second-generation player ejects the recordable type disc on which the data encrypted by the CSS is recorded, without the reproduction.
The second-generation player recognizes the recordable type disc on which the data encrypted by the CSS is recorded, for example in the following procedure.
Firstly, the second-generation player judges whether or not a disc loaded on the player is the recordable type disc. Most second-generation players check whether or not there is a wobble formed on a groove which exists on the disc, to thereby judge whether or not to be the recordable type disc. Moreover, there is a possibility that some of the second-generation players check whether or not a LPP (Land pre pit) is formed on the disc, to thereby judge whether or not to be the recordable type disc.
When it is judged that the disc loaded on the player is the recordable type disc, then the second-generation player judges whether or not the data recorded on this disc is encrypted by the CSS. Then, if the data recorded on this disc is encrypted by the CSS, the second-generation player recognizes this disc as the abnormal disc.